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the process of the poisoning, and at the same time I could study 
the heart in the various stages of poisoning by applying extra- 
stimulations. 
B. The image of poisoning with digitalis. 
If we speak of the image of poisoning that we observe with a 
frog’s heart after injection of digitalis, then we understand by it the 
reaction of the heart on such a dose as occasions disturbances of 
the rhythm and in the end stagnation of the heart. We can arrange 
this image of poisoning into 3 stages. 
1. The beginning of the poisoning in which the undisturbed 
normal rhythm still continues, i.e. every impulse of the sinus venosus 
is answered by all the partitions of the heart with a contraction. 
2. Stage of the disturbances of the rhythm. This stage often begins 
with an alternation of the ventricle which thereupon is converted 
into halving of the rhythm of the ventricle or formation of groups, 
afterwards often alternation of the halved ventricle-systoles, then further 
halving of the ventricle-rhythm. The halving of the auricle-rhythm 
sets in later than the halving of the ventricle-rhythm. 3. Stage of 
the groups of Luciani, usually converting into separate ventricle- 
systoles e.g. to about 16 auricle-systoles 1 systole of the ventricle. 
Then follows a stagnation of the ventricle. These are the 3 stages 
of the image of poisoning, as it shows itself in the ventricle. After 
the stagnation of the ventricle the auricles still continue to pulsate 
either in the normal or in the halved rhythm or in bigeminus- 
groups, whilst frequently variations in these rhythms occur. 
1. First stage. The frequency of the palpitation of the heart slowly 
decreases. The systolic emptying of the ventricle becomes more com- 
plete. We see the ventricle contract during the systoles to a small 
white ball. The duration of the a—v interval increases, towards the 
end of this stage the height of the systoles decreases remarkably. 
We observe at the same time a distinct decrease of the irritability 
of the muscle of the ventricle. Stimulations that before the injection, 
in the beginning of the diastole, caused an extra-systole, must after 
15 minutes be either fortified or be applied later in the heartperiod 
in order to have the same result. Fig. I represents the suspension- 
curves of a frog’s heart in the first stage of the poisoning. At 1 an 
extra-stimulation is applied to the basis of the ventricle towards the 
end of the diastole. No extra-systole of the ventricle takes place, 
but the auricle shows an extra-systole. During the compensatory 
pause the stimulation is repeated at 2, but at a moment at which 
